What are the methods of artificial breeding of cattle and its advantages?

What are the methods of artificial breeding of cattle and its advantages?

In the natural methods of cross breeding explained above the two parents are chosen for selective mating. Other than this there is no human interfer­ence in the process of reproduction. But in artificial methods of breeding after careful selection of parents there is manipulation in the reproductive process so as to yield better results.

Artificial breeding methods are also followed in such instances where there could be a failure in the natural methods of breeding. In the paragraphs below the methods of artificial breeding are explained

1. Artificial insemination:

In this process, semen from a high quality pedi­greed bull is selected and the cows are artificially inseminated. For this purposes there are several mechanical devices to introduce the sperm in the vaginal tracts of the cows. Semen collected from bulls is usually kept frozen at temperatures upto -196°C in liquid nitrogen. At the appropriate time it is brought to normal temperature and used for insemination.

2. Superovulation and Embryo transplantation:

Just as in human beings, in cattle also the reproductive process is controlled by hormones. These hormones regulate the production of ova at a predesignated time and in a predesignated quantity. Superovulation refers to increasing the quantity of production of ova in cows by injecting hormones. For this purpose a good quality cow with a high yield of milk is selected and is given hormonal injections to induce superovulation.

The semen from a good quality bull is obtained and is artificially inseminated to induce fertilization. When em­bryos are formed (more than the normal number), 4-10 embryos are col­lected at a time. The embryos would be in the blastocyst stage because it is at this stage they can undergo implantation. Each embryo is then trans­planted to another cow which is generally referred to as carrier cow or

Surrogate mother:

The pregnancy of the cow continues in a normal man­ner and the birth of the calf takes place after the usual period of gestation. The embryos obtained from the cow after superovulation are usually pre­served by deep freezing techniques by storing them at -196° C. It has been found out that the 7 days old embryos can be preserved for several years by deep freezing techniques and can be used whenever needed. Experi­ments have also been conducted by cutting the embryo into two at very early stages of cleavage and the two pieces so obtained can be made to develop into individual embryos. The progeny produced by this technique will 6e homozygous twins.

The advantages of superovulation and embryo transplantation are many. This technique has helped to increase the number of quality breed cattle which can be later used for breeding purposes.

In vitro fertilization and embryo transfer (IVF and ET) can also be prac­tised in cattle as is done in human beings. The Veterinary college of Agri­cultural university at Hebbal, Bangalore is using this technique to produce quality breeds of cattle.